Tornek-Rayville TR-900 watch – $95,000 (£79,200) at Bonhams Skinner.

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The TR-900 was produced in two batches in late 1964 and in mid-1966 for the US Navy’s Experimental Diving Unit (now known as the Navy SEALs).

Due to the 1933 ‘Buy American Act’ that remained in force, the navy could not directly purchase the Swiss Blancpain watches it had tested and approved.

Instead, a New York importer for Blancpain, Allen V Tornek Co, won a bid to be the US supplier of the rebranded watches.

The name Rayville refers to the official name used by Blancpain since 1932 when the last member of the Blancpain family to run the company, Frédéric-Emile Blancpain, forced a legal name change.

According to scholarship, most of the TR-900s were destroyed by the US government because of the use of radium to the dials. However, somewhere between 30-50 examples are thought to have survived – and Skinner has sold more than half a dozen of them, including one for a record $100,000 in 2017.

Gift from a mate

The example offered on August 9, engraved with military markings MIL-W-22176, was being offered at auction for the first time.

The consignor’s parents had both joined the Marine Corps in the 1950s, with this watch gifted to his father by a fellow officer while in service at Camp Pendleton, California, in the late 1960s. It had been kept in a drawer for over 40 years and was in good order with a generally clean dial, glass and a small chip to the bezel.

Estimated at $70,000-90,000, it took $95,000 (£79,200).